Serum adiponectin levels and tissue expression of adiponectin receptors are associated with risk, stage, and grade of colorectal cancer

Adiponectin has been associated with colorectal cancer (CRC) risk. This study aims to investigate the association of both adiponectin and tissue expression of its receptors with CRC risk as well as clinicopathological characteristics, notably stage and grade. Determination of serum adiponectin and immunohistochemical expression of adiponectin receptors in adenocarcinoma/normal colorectal tissue was performed in samples from 104 newly diagnosed CRC patients and 208 age- and sex-matched controls. Multiple logistic regression odds ratios and 95% confidence intervals for CRC risk were derived, controlling for a series of covariates. Serum adiponectin was negatively associated with CRC risk (odds ratio, 0.72; confidence interval, 0.53-0.99) and also with tumor grade (P = .05). Expression of both adiponectin receptors was stronger in adenocarcinoma vs normal tissue (P = .001). AdipoR1 expression was negatively associated with nodal stage (P = .03); AdipoR2 expression was positively associated with tumor, node, metastasis stage (P = .01). Established positive associations with red meat consumption and diabetes, and negative associations with physical exercise and plant food consumption were confirmed along with a more than 60% higher risk associated with central obesity. Adiponectin levels and tissue expression of hormonal receptors seem to be associated not only with CRC risk but also with components of clinicopathological characteristics; given power limitations, these results should be interpreted with caution. The exact nature of the association and the underlying pathophysiological mechanisms need to be further examined in large prospective studies assessing adiponectin and its receptors as novel targets for exploring CRC growth.